The present invention relates to a control apparatus for an electric motor and a control apparatus for an electro mechanical brake, and more particularly to a control apparatus for an electric motor of an inverter system and a control apparatus for an electro mechanical brake to be used for a vehicle such as an automobile.
Controlling a torque of an electric motor by an inverter is applied to various electric motor control systems of a vehicle such as an automobile, e.g., an electric power running system, an electric power steering and an electro mechanical brake, respectively of an electric power automobile.
In such electric motor control systems, a power source input to an electric motor is short circuited in an abnormal state such as a turn-off of a main switch (e.g., refer to JP-A-9-47055).
In an electro mechanical brake using an electric motor as a thrust force source, as a fail safe for a defective wheel with a defect in a control system including software and hardware, a fail open function has been proposed which releases a thrust force of the defective wheel in order not to brake the vehicle (e.g., refer to JP-A-2002-39240 and JP-A-2003-14014). With the fail open function, when an abnormal state occurs, controlling an electric motor is stopped completely and a supply of electric energy to the electric motor is stopped to thereby release a thrust force.
An electro mechanical brake is installed to each of the four wheels of an automobile. If a braking force is applied only to a particular wheel during running, a yaw moment is applied to the vehicle about the axis of the braked wheel. This yaw moment curves the vehicle running direction depending upon a vehicle running speed (vehicle speed) and a road condition.